Lattice mat



F. H. RU FPEL.

Feb. 13, 1945 LATTICE lMAT -Filed July 29, 1942 2 Sheets-Sheet l 27 26 z Z7 /ff Feb. 13, 1945 F. H. RUPPEL LATTICE MAT Filed July 29, 1942 2 Sheets-Sheet 2 Patented Feb. 13, 1945 UNITED STATES` PATENT OFFICE LATTICE MAT Frederick H. Ruppel, Pasadena, Calif. Application July 29, 1942, serial No. 452,681

` 4 claims. `(C1. 94-13) This invention `relates to uniplanar metal mats of open lattice type, and more particularly to composite mats formed from a large number of small mats of convenient size for handling.

The invention is particularly applicable to the construction of foundation mats to be laid on the ground for forming airplane runways, roads, gun foundations, and similar purposes. c,

. An object of the invention is to provide areticulated mat as a foundation to be laid on the ing capacity with minimum `weightfof metal.`

`1 0 ground, which has relatively great lo-ad-support- Anotherobject is to provide a foundation mat to be laid on the ground as a support for moving loads in which the mat is` of such construction movement in a. horizontal direction along 'the ground,` wherebyconcentrated loadson` the mat tending to depress it into the ground directly `under the load, places themat in horizontal ten-` sion so that the load is suspended from the ground on each side of the load for a substantial dis'- tance.

15 `as to have a very large frictional resistance to' f Another'object isto provide a large area foundation mat composed of a large number of units sulciently small to be conveniently handled, and

` of such construction as to be readily and strongly joined together. c c Another object is in the direction at right angles thereto, for convenience in shipment and handling,.and to adapt l the structure forfdiierent purposes. c

Another` object is to provide a fastenerand a fastener tool for rapidly and strongly interconwith the invention.

The present invention represents a further de- Ivelopment of the invention in my PatentNo.

prises two sets of bars `crossing each other at an angle and pivotally connected at their `crossing point by rivets or bolts. That construction can to provide a mat `capable of c being contracted` in one dimension; and elongated `35 necting a plurality of unit mats in accordance 1 .thereover, thereby providing great resistance to lateral movement along the ground surface. The bars of the mat function as supporting members in tension anchored between the bars imbedded in the earth on each side of the load. The inl vention is particularly useful for constructing landing fields for military aircraft, or for con- `gether.

The invention is `also useful in the construction of military bridges by virtue of the fact that a large` number of single units can be quickly assembled into a strip that can be laid directly on stringers supported on boats to form a pon-f `toon bridge, or similar strips can bequickly secured between upper and lower side beams toform therewith a truss beam of any desired length.`

The invention will now be more fully explained by describing certain specific embodiments thereof in connection with the drawings, in which Fig. 1 is a plan view of a portion of a large lattice mat in accordancewith the invention, showing the intersecting portions of four unit mats;

Fig. `2 is a greatly enlarged detail section of one of the joints, taken in the plane II-II of Fig. 1;

Fig. 3 is an enlarged plan `View of one of the joint intersections, with the fastener removed;

Fig. 4 is an elevation view, partly in section, of

a landing eld in which a mat in accordano with the invention is laid on soft ground;

Fig.` 5 is a plan View of a unit mat in accordance with the invention, in folded condition for be expanded and contracted accordingto the reinforcing unit of my earlier patent can form.

'transportation and handling;

Fig. 6 is an elevation view of a fastening element and a tool for applying it, the tool `and fastener being shown in position just prior to applicationof the fastener to the mats;

Fig. 7 is a detail section, `showing the fastener clamped onto the mats, with the tool;

Fig. Sis a detail view, looking at one ofthe jaws of the fastening tool;

Fig. 9 is a plan view, showing a fabric strip in accordance with the invention, used in the construction of a pontoonbridge; and

Fig. 10 is an elevation view of a portion yof a long truss, in accordance with the invention.

Referring, first, to the plan view of Fig. l, there is shown a section of a mat in accordance with the invention, the view showing portions of four adjoining units 2D, 2l, 22 and 23, respectively, all of which units are`identical swith each other. Each unit comprises a plurality of parallel lower bars 24 and parallel upper bars 25, the latter extending'across the lower' bars at right angles thereto, and all the bars being intercorre nected at their points of crossing by rivets 26 which permit rotation between the upper and lower sets of bars, such as to swing the bars froml positions normal to each other, as shown in 1, inl/ pOSltiO-lls in Which all th'e lippe? blfs' lie against each other, the lower bars'rlie against each other, and the lower and' upper bars" are very nearly parallel to each other, as shown Figi.- u. In this position the unit can be conveniently shipped and handled, and can lde spread out'into the operi condition Shown iii Fig. r1 at the point of assembly'.

Tiielower and'upper Vliars 24 and' 25, respectively, can be' of' a variety o'f c'ro'ss' sectional baclli's of the bars close together, reduces the "that the exposediianges df'tlie lower back ifierritiers;l into tlie ground andanohdr themselves against' horizontal movement donn-a1 to trleir length. Tiiei flanges of tlie iipper oliaiiriels' pro'- eferrng to Fi'g.`4, there is shown a'n airplane riir'l'way formed'b'y' laying a large' mat 3'0, in 'ac'- 'ooldlnoe With the prescrit invention, oli soft onboggy ground 3l'. The ground may be' so soft'. thatif Athe' mat' 30' were'not employed the vvlre'els- 32" o'fl'an .airplane 33`would be hopelessly mired. However, when the mat, in accordance with the present invention", is" laid" on tl'ie' soft ground-- and the airplane tnereover", the weight' of the airplane causes the that to' belly dOWn b'elOW a.' s'hor't distance below the sur/face of the soft ground, the" ground immediately below the airplane alrcirdingvery little resistance to the" settlingA ofthe mat tliferetliroiigli. However, the deflection of the' mat' from its normal flat shape to-tliearcuate' shape, 'indicated at 34, places "the mat in tension' so that itA carl" be depressed `only avery short distance Without either stretching or pulling` iii from the' si'de's.` The bars 2li and 425 which' are placed iri'telrsion, 'are kmade of sufficiently lieavy stock', and placed `suliicier'ltly close together,v so thatthey wil'lnot stretch materially in response tothe forces" appliedt'o' them.

-Hence' the* lnaty cannot sink` into'the'ground'l very farm resporis'eto-tlieload ditlie` airplaneiiiiles's the mat pulls in ifrol'ii the s'ides.- Such pulling in from the sides is prevented by virtue of the fact that the bars are imbedded in the ground and yafford great resistance to horizontal dragging movement through the surface earth. As va result of these inherent anchoring properties of my mat, it is capable of supporting relatively enormously heavy vehicles for movement over ground so soit that the vehicles would be hopelessly mired Without the mat.

A's is;v apparent from an 'inspection 'of Fig. 1, the

. bars 2taiid 25` of eacii unit-26, 2l, 22 and 23 extend diagonally of that unit. It is possible to connect the individual units together in any decompositemat-intllee'ld Y accordance with thegpreseritjinyentioii, `1

stantiailly the samej distance.

sired manner so that in a large roadway or runway the individual bars 24 and 25 may r-url either parallel Iand'normal respectively to the direction of traflic, or diagonally with respect to the direction of traic'. The latter arrangement is preferabl'ei for several reasons. One reason is that itpermits straight edges on the composite mat,

wliiclll saves material, particularly in the case f or a relatively narrow roadway; dii-other reason is that the tensile stresses extending across' the runway, as" described in connection' with 4, are distributed over both thelower 'ba'rs '245 and the' upper' bar's 25. It isv also olf interest `to note that when the tensile' stressesre'alpplied to' the mat diagonally with 'lf'espelzt'tothe bars 24 and 22d they tend to defor-ni' theN or'ieniligsY deii'ne'd by tl'ie bars' from square to 'diamond-'shape'. Such movement of the bars is resisted by' tlie'ompression"v di earth therebetween. It is well' known that woven fabric will yield'fnorejwlieri stretched on Ythe loi-agv than when sfl-,retcliedl in Ithe direction oreitlier the warp or-vvo'of; fTliis is likewise triie of' roy-matarrdwiien it is laidY wil-.ir diev out tirait-they los of suoli Aa dattie as to; permit rapidi" assembling" `0`f"tf1fe" individuali" I'IiatS" illt a satisfy these-requirements byf employing clamps 351 wht-en are pressed arodiidoverlappi'rig oars 24 and-251ertlieadjaeentiildividtal-rriats. rl'iiisrjeferri-ng to the individiial joint 3s' -petweer'ijtlie individual mats 2o and 2 l, the-'dpperjoars 25, 25 of tlie two-'mats lapeacl'jother fora length equivanddownebetween th'efftw` bars 24- and-25 of the other mat: at the"v other`endl,'tlief l'oweren'dsof the `clamp being cli-nchedi'tgainsty the undersides .9i the lower bars 24,14: .Thisproduc'es a strong joint becausethe clamp hasl to resistmovement only alongr its/length. Thus vertical movement of mat 20 with respectto mat` 2 is pre vented by engagement of the underbars A24 oflrnat warjd 'movement' offmat' 2li with respect teniet 2l isi similarly prevented jbyjeiieageiiient ofthe bars 25A ofiiiat 2li againstb'ars 24 or niet 2|. Relative horizontal movement ofthe 'two 'mats in adirec'- tionat right anglesto the `plane of the clamp` 35 is prevented inone direction by `contact of the upper bars 25, of the two mats `with each other, and in the otherdirection by contact of Y the lower bars 24,` 24` ofthe two mats with each other. v A

` Tospeedily install the clamps I `provide al specialtool (Fig. 6)` which is similar to a con-` ventional bolt cutter, except that the jawsare different. Thus itcomprises a pair of long han-1 dles 4| pivotally connected together by a pivot 42 and having short arms 43 pivotally connected to the upper ends of a4 pair of jaw members 44 which are fulcrumed to each other by pivots interconnected by yokes 46. 'Ihe lower, or working, ends of the jaws 44 are shaped to fit around the bar members 24 and25, as indicated in Fig. 7when the jaws are forced together. `Intheir open position, as shown in Fig. 6, the lower ends of the jaws are separated a suiicient distance to .receive and frictionally retain U-shaped clips 35a from which the clamps 35 areformed. The

. in Fig. 8, the tips of the jaws have grooves `lll therein into which the clips t.`

After a clip 35a has been positioned between the jaws of the tool, as shown in Fig. 6, itis mats at a joint until thecross bar of the clip seats against the iianges of the upper bars 25. Such seating may be positively effected by the operator placing his foot between the handles` 4|, as shown in Fig. 6, while supporting the handles, one on each hand. As soon as the cross;

bar of the clip is seated, as described, the clip is converted into the clamp 35, as shown in Fig. 2,

by simply bringing the handles 4l, 4l of the tool 40 together, which forces the jaws of the tool into theposition shown in Fig. 7. The ends of the clip are guided as they are bent under the bars 24, 24 .by extensionslla of the grooves :il into the inner portion of the jaws. i After the clamp has been set, as described, the handles 4l of the tool 40 are spread to open thejaws, whereupon Fig. 6, at the time they are forced down into4 place. The advantage is that it facilitates the placing of the clipV when the bars to be fastened are not already in close contact with each other. Then as the clip is forced down into place the titled arms of the clip function to force the Vbars of the two mats tightly against each other.

When a mat is to be broken `up into individual mats for removal, the upper bars of the clamps way or roadway on softground# However,l there -are otheruses for long `sections of latticexwork interconnected in the particular manner `herein i disclosed. Two such uses are disclosedl in Figs.

4lattice-work is formed by interconnecting a plu--` ralityfof -un'it mats 5I, 52 and 53, in accordance with the'invention, and isusedV as awbaseor roadway `for apontoon bridge, the strip being laid upon -stringers 54 extending between pontoons 55.4 The stringers 54 arefspaced apart bycross beams 56, and the lattice work 56is secured -to the stringers 54 where each barI 24 and 25 of the mat overlies the Stringer. Attachment between the bars and the stringers maybe effectedby bolts extendingthrough apertures provided in thebars 24"and 25. "Such apertures are shown at 10 in i the'mat unit 23 of Fig. 1. i

` Whena load is run across the bridge `of Fig. 9,

`forced down over the overlapping bars of the two theycrossbars of the lattice .work are placed in tension and are capable of supporting substantial loads. Furthermore the mats provide the important function of `providing diagonal bracing between the stringers` 54, 54 sothat the composite structure consisting of the stringere' 54, 54 and the mat 5U constitutes a horizontal truss beam. This is important in apontoon-bridge since it prevents lateral bending or defiection of the bridge asthe result of strong'currents, and

the like. i. i i

Obviously the same principle last described in .connection with the pontoon bridge may be l utilized for producing vertically disposed truss beams for use `on such members as long-span bridges, and the like. Such an arrangement is shown in Fig. 10, Consisting of an upper beam member 66 and a lower beam member 6l, which 35 can be quickly `cut with a conventional bolt Heretofore my mat has beenI described in detail only with reference to its use as an airplane runare maintained separated by vertical .members 62 at frequent intervals and are maintained against sagging by a-.Web of lattice work 65 consisting of a plurality of unit mats '66, 61 interconnected together by clamps `35, as previously described. The individual bars of the mat 65 i aresecured to the upper and lower beams 60 and 6| in any desired manner, as by bolts or nails.

i All the .structures shown and described are particularly useful for military purposes, because the individual mats can be readily transported and handled in the collapsed form shown in Fig. 5, and can be quickly expanded and connected together with the `clamps 35 at the point where they are to be used.n

Obviously, the bars 25 and 26 `may be made of various sizes. A suitable size of channel that has been employed is 3A" wide by deep. The upper and lower bars may be joined together by g X 34; rivets, and the clamps 35 may be of T35 pencil rod., Individual mats may be conveniently dimensioned 10'- x 12 fully extended size (when the upper and lower bars are normal to each other). Such a mat, when collapsed to the condition shown in Fig. 5, will be approxi mately 14 x 3" long and 15%" wide. With the rods spaced to define squares 6" on a side, such a mat will have a total weight of approximately 200 pounds and can be handled by two men. It

will weighapproximately 1.62 pounds per square foot of area and is capable of supporting 20-tcn trucks, having conventional tires, even on very soft soil or sand.

Although for the purpose of explaining the invention certain specific embodiments thereof have been disclosed and described in detail, it is to be understood that various departures from the exact construction shown can be made without. departinei from inventimn which isi to'y be to exitem; set; 'forth-im the. ap.- pended.. claims. i e

claim;

A-, composite. mat, of the tapa described=, con.

sieting; or ai plurality of:` similar: unit lattice-work mats connected` together, inswtnich each unitl mat comprises aflattiee-worle consisting:` ofi alcmver set of` parallekspacedl apart. bars., and. an' upper set of parallel. spaceaparti bacsoverlyingvl said lower sea. the bars) of the upper set. crossing` the bars of the lower set. at.1 an angle. and each lear oin one `set being;` pivotallsi secured ta eacnl of the other sety ati itaintersectiona tnerewithallk said bars extending. diagonallp withl respect, te the boundaries of, the.l unit, mamandi eachadjoining pai-rV of; unitd matsy having: tlziel` .ad-jacenty ends of their upper bars in side overlapping relatien--with eachother and havingthe adjacent4 ends et: their lower. bars, in side, overlapping relation withieach other',3 and diagonal tie means for securing; each set of overlappingi bars'. together,v said diagonal tiemeans extending around thefoverlappingbars 'inx the; direction of a diagonal of, thel paralleloggrams formedv tlfiereby.A

2; A composite maty as, described; in claim 1,

'ini` which saldi tie means fior. securing; eachl set ofl overlapping' bars, togethen comprises a. .rod memlozer.` extending; diagonally across the topf of said overlapping portions of said two upper` bars, thence;dewnwardln'atzoneend inthe angle betweenthe upper and lower barsf'of. one mat: and

downwardm at the @then endin the angie be.

anaemia tween the upper and lower bars.: of; the citlsierL the, ends. of, the4 downwardlgs(l extendingportions heiney clinched under-the lower bars or the re- 3.k A.. composite matA as. described; inAk claim l,

in-vwhichJ the end oi, each bar in each. unit mat' extends a short distance beyond the last interlsecting -bar of the. saine. mat, whereby; it, overlaps the. bar in the opposite set: in the adjoining unit mat.

` 4f A composite webbing" consisting of, a. plurality of similar latticevwork unitsconneoted tegether in Which-eachunit comprises af. lattice work, consisting oa lower set of, parallellspaced.- apartbars and an upper set. of parallelspacedapart bars overlying said' lower set, the. bars of vthe upper setvcrossing the bars of? the lower set at` an. angle. and eachv bar oiv oneset. pit?!- otally secured to eachnbar of. the otherL set' af intersection therewith, allfsaid bars extending diagonally with respect to., the boundaries ofl the unit, and'each. adjoining pair. of. unitshavingktlie w 

